· Luke Faragher · ONSIM  · 3 min read

BT ISDN Switch OFF 2025

BT Announce ISDN Switchoff scheduled for 2025

BT Announce ISDN Switchoff scheduled for 2025

As the impending switch-off looms ever closer we wanted to offer a gentle reminder to any customers still considering or* currently using ISDN PBX phone systems that BT confirmed that the ISDN network will be switched off by 2025 forcing customers of the UK’s roughly 3 million ISDN lines to migrate to IP services whether or not they are available, stable or suitable.

What is ISDN?

ISDN stands for Integrated Services Digital Network – ISDN is the transmission of voice and data traffic over the traditional copper wire circuits of the public switched telephone network (PSTN). For years ISDN has been the mainstay of business communication due to their reliability and widespread use. ISDN channels are sold in various configurations depending on the amount of simultaneous calls required – BT previously offered ISDN2 and ISDN30 connections on their website.

What is happening and when?

By 2025, BT will switch off the ISDN network, although this may seem a long way off, it is likely that the existing ISDN network will become impaired before this date as it is likely that they will not make any future improvements to this legacy platform. BT (and most others) are touting the replacement for ISDN as VoIP or SIP (session initiation protocol) only based services which generally speaking enables a phone line to be brought to you via your internet connection.

Why is this happening

The ISDN systems have become old technology and the cost of maintaining and supporting them now outweigh the benefits (revenue) for BT/Openreach. This looks (our speculation) to be driven by Openreach who maintain the PSTN network for BT.

What alternatives are there?

Most are heavily pushing (BT Included) VoIP Services to replace ISDN whether they are suitable or not – for the operators these offer huge margins and there are a range of benefits for businesses to using VoIP but the major draw back is that not all will have stable enough internet. As an alternative, there are also ‘converged’ systems, ones that merge Fixed (or VoIP) services and mobile networks that offer all the features and benefits of VoIP but aren’t reliant on your internet connection.

Our thoughts on the BT ISDN Switch off

Whilst we agree there are numerous benefits of replacing your old ISDN based PBX forcing everyone to use VoIP when there are huge numbers that don’t have access to decent fibre seems a bit of a “catch 22”. What BT are essentially is saying is “You can have a more modern phone system, that’s cheaper and has more bells and whistles but dependent on your internet it may or may not work for calls…” It begs the question; will BT loose business customers in droves as they move to better services? If they do you can’t say it’s been brought on by themselves.

Fortunately we have developed the answer – a modern, cost effective phone system that blends all the benefits of VoIP but can also use mobile networks (not the internet or data) to route calls if your internet isn’t great or you need to be highly mobile. You can learn more about our mobile first phone systems here – click here.

*As of 2020 businesses can no longer buy ISDN through BT.

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